

// 模块1
mod front_of_house {
    // 模块嵌套
    pub mod hosting {
        pub fn add_to_list() {}
        fn seat() {}
    }
    // 模块嵌套
    mod serving {
        fn take_order() {}
        fn serve_order() {}
        fn take_payment() {}
    }
}

pub fn eat() {
    // 绝对路径
    crate::front_of_house::hosting::add_to_list();

    // 相对路径
    front_of_house::hosting::add_to_list();
}